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The research on alfalfa under subsurface drip irrigation (SDI) includes: water consumptions (WC) rule, water irrigation rule, salinity distribution rule, suitable discharge of drip tape, depth of drip tape buried, Alfalfa plant and row spacing, layout pattern of subsurface drip irrigation system etc.The result shows, under the particularly aridity climate in Xinjiang region, the alfalfa planted more than 2 years with SDI,the maximal water consumptions rate(WCR)of alfalfa is about 6.8- 9.5mm/day, the WCR of 35cm buried is more than 20cm buried, the WCR in either the first stubble or the third stubble is less than 3.0 mm, the WCR is more than 6.0 mm in the second stubble from late June to early August—the highest temperature period of the year. WC of the whole growth is about 623.5-685.8mm, and water quantity of the whole growth is about 458.3-609.0mm; The WC is about 359.5-379.6mm, and the max water quantity is about 247.7-330.2mm. irrigation interval during the whole growth is about 10-20,and water volume is about 20-50mm at one time. SDI has the advantage of diluting salinity, the salinity of 10 m buried is less than 35cm buried obviously. Result shows that the alfalfa yield with 35cm buried is higher than it with 20cm buried, and the yield with lower discharge is higher than it with bigger discharge, average yield for dry matter alfalfa is more than 15t.hm-2. Under the water quantity is 37.5mm, if drip tape with different discharge is buried 20cm and 35cm, the side water wetting width in the soil is 50~80cm, and the lengthways water setting depth is 40-48cm, if drip tape is buried 10cm,the side water wetting width in the soil is about 60cm, and the lengthways water setting depth is less than 30cm. Accordingly, We select the drip tape discharge is less than 2.0L/h,spacing is between 70 to 90cm, each lateral controls 4-6 rows, the drip tape is buried below 20cm.Finally, the conclusion is determinate that alfalfa cultivate under subsurface drip irrigation (SDI) is feasible, and more effective irrigation model.
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